Add default cross-profile package APIs

Add cross_profile_apps.xml and
DevicePolicyManager#getAllCrossProfilePackages. This sets the list of default package names set by the OEM for the user to approve/disapprove for
cross profile communication during managed provisioning setup.

Some Javadoc can be improved once all CLs are in, since different APIs
should refer to each other.

BUG: 136249261
BUG: 144577776
BUG: 145970297
Test: atest com.android.server.devicepolicy.DevicePolicyManagerTest

Change-Id: I214b521ffc7fb0179bff1ca65d6bc2a9f8decea3